Personally I'd vote for the BSkyB platform. There are so many problems with digital terrestrial television technology still to be satisfactorily overcome - and the only reason for the government's enthusiasm for terrestrial digital is so that they can flog off part of the Band IV and Band V UHF spectrum. Antenna quality and the deterioration which UHF aerials suffer from with time can cause significant post-installation problems. Far more so than with the pretty reliable Sky system (just make sure that you employ a specialist installer, not some barely trained ex-milkman working on fixed installation appointment times..)
BSkyB appears expensive because of that silly Sky+ system. What's the point now that recording is now possible on domestic DVD recorders?
Unfortunately all the BSkyB receivers bar the elegant Sony VTX-S760U look like something knocked up by a Practical Wireless reader in his garden shed. ("This week, Oi 'av mainly been buildin' sat-or-light boxes"). Hence persuading the memsahib to accept not only a small dish antenna on the side of the stately pile but also an ugly looking biscuit box on top of the TV may be a bit difficult... Mind you, the terrestrial digital boxes look rather like those bits of cr@p you normally see sitting on top of the TVs in most Yank hotels.